Like human armies, army ants trail crowds of hangers-on

Like human armies, army ants spell trouble for anything that finds itself in their path. The insects make a habit of killing organisms, often much larger than themselves, breaking them into pieces and dragging the morsels back to their bivouacs. But they do not eat everything. Rubbish piles full with discarded bits of prey are a feature of army ant bases.

Where there is carrion, there are usually scavengers. But little is known about which animals scavenge on army ant leavings. As recounted in a paper in Ecology & Evolution, Christoph von Beeren at the Technical University of Darmstadt and Daniel Kronauer at the Rockefeller University in New York, both entomologists, went to the rainforests of Costa Rica to find out. They found an entire ecosystem in miniature thriving among the leftovers.